More than a billion people may be at risk for vitamin D deficiency and its associated diseases, according to a 2007 report in the "New England Journal of Medicine." People who don't eat fish, drink milk or have little exposure to sunlight may have dangerously low levels. Researchers continue to find more diseases associated with vitamin D deficiencies. Because the vitamin plays a key role in brain cell health, scientists are wondering if the deficiency causes memory loss.
Benefits of Vitamin D
Vitamin D is often associated with bone health, as it helps regulate blood calcium levels. Without vitamin D, bones cannot regenerate properly. A deficiency often leads to rickets in children and osteopenia and osteoporosis in adults. Vitamin D also controls calcium levels in brain cells and regulates cell growth and death, which is of particular interest in connecting deficiencies to memory loss. It also protects neurons from free radical damage.
Causes of Memory Loss
As brain cells die every year, memory loss may be occurring in people as early as their 20s. Your short-term memory gradually declines, causing you to forget details of recent events. The condition worsens when you experience head trauma, depression, dehydration, or alcohol and drug abuse. But among these causes, scientists cannot agree if vitamin D deficiency should be included. University of Wisconsin researchers recently learned that people with vitamin D deficiencies performed poorly on cognitive tests. The study concluded that there is an association between low vitamin D status and cognitive impairment, but the deficiency did not cause cognitive deterioration.
When you are vitamin D deficient, you may also experience brain inflammation, which is a condition seen in Alzheimer’s diseases patients and others who experience memory loss. Researchers at the University of Cambridge and University of Michigan found that people with low levels of vitamin D performed poorly on cognitive tests compared to those with healthy levels. In another study, Alzheimer’s disease patients with sufficient levels of vitamin D performed higher on mini-mental state examinations compared to those with insufficient vitamin D, according to the Vitamin D Council. The findings showed a relationship exists between vitamin D status and cognition in patients.
Best Vitamin D Sources
Our bodies can synthesize vitamin D from exposure to sunlight, which means the nutrient doesn’t always have to come from our diets. For some, regular sessions of sunbathing are all that is needed. About 30 minutes of direct sunlight in the summer can result in the production of over 10,000 international units of vitamin D, according to the Vitamin D Council. Others who work in offices or live in northern climates may receive less sunlight and will have to consume natural sources or supplements. Fish, such as salmon and cod, fish oil products and milk are high in vitamin D. For healthy adults and adolescents, adequate intake levels established by the U.S. Institute of Medicine of the National Academy of Sciences are between 200 and 600 international units daily.
We only consume too much vitamin D through overconsumption of supplements, according to Janice Thompson and Melinda Manore, authors of "Nutrition: An Applied Approach." A person who has taken too many vitamin D supplements may experience weakness, loss of appetite, constipation, mental confusion, vomiting, excessive urine output and extreme thirst, all of which are symptoms of hypercalcemia. To know your vitamin D status, see you doctor about getting tested.